A device system and method for preparing dichloroethane by ethylene oxychlorination

Abstract

The application provides an ethylene oxychlorination device system and method for preparing dichloroethane, the device system comprising a reaction device, a quenching device and a gas-liquid separation device connected in a loop; a catalyst is arranged in the reaction device; a plurality of heat exchange devices are arranged in the reaction device from bottom to top; a spraying device and a gas distribution device are arranged between adjacent heat exchange devices; and a plurality of gas-solid separation devices are arranged on the inner top of the reaction device. In the application, the fluidized bed reaction device for oxychlorination is precisely controlled in different bed layer reaction temperatures through staged heat exchange and liquid spraying of dichloroethane; the bed layer catalyst particle size distribution is improved by optimizing the bed layer position of catalyst recovery in the gas-solid separation device; and the oxygen content in different bed layers is regulated by optimizing the staged addition of oxygen, so that the ethylene ablation rate is low, the hydrogen chloride conversion rate is high, and the crude dichloroethane purity is high.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of dichloroethane preparation, and particularly relates to a device system and method for preparing dichloroethane by ethylene oxychlorination. BACKGROUND

[0002] Polyvinyl chloride is one of the five general resins, which is mainly generated by polymerization of vinyl chloride (VCM) monomer. At present, there are mainly three synthesis processes, namely acetylene method, mixed alkyne method and ethylene method. Among them, the ethylene method becomes the mainstream process in the industry due to low production cost and high product quality. In the ethylene method production process, ethylene is first subjected to chlorination or oxychlorination reaction to generate 1,2-dichloroethane (EDC), and then the 1,2-dichloroethane (EDC) is subjected to high-temperature cracking to generate vinyl chloride (VCM).

[0003] In the phosgene method for producing isocyanate, most of the chlorine atoms are discharged in the form of hydrogen chloride after carbonyl substitution, and a large amount of by-product hydrogen chloride brings great pressure to the operation of the enterprise, which restricts the development of the isocyanate industry. In the ethylene oxychlorination process, ethylene, hydrogen chloride and oxygen are reacted under the action of a catalyst to generate dichloroethane and water, realizing the cyclic utilization of the chlorine ion source and producing chloroethylene products, which can produce greater economic benefits when matched with the isocyanate device.

[0004] In the existing ethylene oxychlorination reactor operation, raw materials ethylene and circulating gas, hydrogen chloride and oxygen are respectively sent into the reactor through the feed distribution main pipe, and are reacted under the action of copper chloride catalyst to produce dichloroethane and water, and by-products such as carbon tetrachloride, trichloroethane and trichloroacetaldehyde are also generated. The built-in vertical cooling coil in the reactor removes the reaction heat by hot water vaporization, and generates steam as a by-product. The secondary cyclone separator at the top of the reactor collects and recovers the copper chloride catalyst entrained in the reaction gas. The high-temperature reaction gas coming out of the top of the reactor is rapidly cooled by capture water in the quenching tower, and absorbs the unreacted hydrogen chloride. After quenching, the reactor is separated by condensation, and the crude EDC is sent to the washing unit and the subsequent refining unit. The non-condensable gas is compressed and then enters the reactor again as circulating gas. The excess non-condensable gas is sent to incineration after being recovered by deep cooling.

[0005] The ethylene oxychlorination reaction is carried out at low pressure, and the reaction temperature is 200-250℃. Under normal circumstances, the ethylene conversion rate is 95%, and the chlorination conversion rate is 99.4%. Under the same feed ratio, high temperature will exacerbate the ablation of ethylene and the generation of impurities, thereby reducing the yield of dichloroethane generated from ethylene. Due to changes in catalyst activity and fluidized bed state, in order to ensure the stability of the hydrogen chloride conversion rate, the reaction temperature must be increased. Therefore, the ethylene yield and the hydrogen chloride conversion rate are mutually restrictive, and it is difficult to achieve both.

[0006] CN1141282A discloses a process for producing 1,2-dichloroethane by oxychlorination of ethylene, which comprises contacting a catalyst composition with a mixture of ethylene, oxygen or an oxygen-containing gas and hydrogen chloride in a reaction zone and recovering 1,2-dichloroethane from the effluent of the reaction zone. The improvement comprises using a catalyst composition containing about 2% to about 8% (by weight) of copper, about 0.2% to about 2% (by weight) of an alkali metal, about 0.1% to about 9% (by weight) of a rare earth metal and about 0.05% to about 4% of a Group IIA metal, all weight percentages being based on the total weight of the catalyst composition.

[0007] CN105073255A discloses an oxychlorination process in which ethylene is converted to 1,2-dichloroethane in the presence of a supported copper catalyst, the improvement comprising: using a supported catalyst prepared by: (i) in a first step, impregnating an alumina support with a first aqueous solution comprising copper, an alkaline earth metal, and an alkali metal to form a first catalyst component; and (ii) in a subsequent step, impregnating the first catalyst component with a second aqueous solution comprising copper and an alkaline earth metal to form the supported catalyst, wherein the second aqueous solution is substantially free of alkali metals.

[0008] However, the above method cannot guarantee high conversion rate and yield of ethylene while achieving high conversion rate of hydrogen chloride. Summary of the Invention

[0009] In view of the problems existing in the prior art, the present invention provides an apparatus system and method for producing ethylene dichloride by ethylene oxychlorination. By implementing staged heat exchange in a fluidized bed, liquid ethylene dichloride spraying, staged oxygen addition, and catalyst recovery in a gas-solid separation device, the problem of mutual restriction between ethylene ablation rate and hydrogen chloride conversion rate in ethylene dichloride production is solved, thereby achieving reduced ethylene consumption and improved hydrogen chloride conversion rate, while reducing by-products such as trichloroethane and carbon tetrachloride, improving the purity of crude ethylene dichloride, and reducing downstream refining energy consumption.

[0010] To achieve this object, the present invention adopts the following technical solutions:

[0011] In a first aspect, the present invention provides a device system for preparing ethylene dichloride by oxychlorination of ethylene, the device system comprising a reaction device, a quenching device and a gas-liquid separation device connected in a loop;

[0012] A catalyst is arranged in the reaction device; multiple stages of heat exchange devices are arranged in sequence from bottom to top in the reaction device; spray devices and gas distribution devices are arranged between adjacent heat exchange devices; and a multiple stages of gas-solid separation devices are arranged on the inner top of the reaction device.

[0013] The reaction device of the ethylene oxychlorination device system for preparing dichloroethane is sequentially provided with multiple stages of heat exchange devices from bottom to top, a spraying device and a gas distribution device are arranged between adjacent heat exchange devices, liquid dichloroethane is introduced into the spraying device, and the spraying device and the heat exchange device are used to jointly control the temperature of different bed layers in the reaction device; oxygen is introduced into the gas distribution device to supplement oxygen for catalytic reaction and to control the oxygen content in different bed layers, so that high conversion rate of hydrogen chloride at the top of the reaction device is realized. The device system has reasonable design, is convenient to control, ensures high conversion rate and yield of ethylene, and realizes high conversion rate of hydrogen chloride.

[0014] The spraying device and the gas distribution device are not limited in detail, and devices in the prior art can be used to realize uniform distribution of liquid dichloroethane and oxygen in the reaction device.

[0015] Preferably, the heat exchange device comprises vertical heat exchange members.

[0016] Preferably, the number of stages of the vertical heat exchange members is 2-5, for example, can be 2 stages, 3 stages, 4 stages or 5 stages, preferably 3 stages.

[0017] Preferably, each stage of vertical heat exchange members comprises 20-30 groups of U-shaped tubes, for example, can be 20 groups, 22 groups, 24 groups, 26 groups, 28 groups or 30 groups, but is not limited to the listed values, and other values not listed in the range are also applicable, preferably 24 groups. Each group of U-shaped tubes contains 2n tubes, and n is 5-12, for example, can be 5, 6, 7, 8, 9, 10, 11 or 12.

[0018] Preferably, the diameter of the tubes is independently 50-100 mm, for example, can be 50 mm, 60 mm, 65 mm, 70 mm, 80 mm, 90 mm or 100 mm, etc., but is not limited to the listed values, and other values not listed in the range are also applicable, preferably 65 mm, 80 mm or 100 mm.

[0019] Preferably, the length of the tubes is independently 3-15 m, for example, can be 3 m, 4 m, 5 m, 6 m, 7 m, 8 m, 10 m, or 15 m, etc., but is not limited to the listed values, and other values not listed in the range are also applicable, preferably 4-5 m.

[0020] Preferably, the number of U-shaped tubes, the diameter of the tubes and the length of the tubes in the same stage of vertical heat exchange members are uniform.

[0021] Preferably, the positions of the U-shaped tubes in adjacent vertical heat exchange members are staggered, which can effectively improve the fluidization state of the catalyst in the reaction device and reduce the bubble diameter in the bed layer, thereby improving the mass transfer effect.

[0022] Preferably, the vertical heat exchange member is connected with a boiler water conveying pipe.

[0023] Preferably, the number of stages of the gas-solid separation device is the same as that of the vertical heat exchange member.

[0024] Preferably, the gas-solid separation device comprises a cyclone separator.

[0025] Preferably, the reaction device is a fluidized bed reaction device.

[0026] Preferably, the bottom side of the reaction device is provided with a first raw material conveying pipe and a second raw material conveying pipe.

[0027] Preferably, the first raw material conveying pipe is provided with a first heating device.

[0028] Preferably, the second raw material conveying pipe is provided with a second heating device.

[0029] Preferably, the gas distribution device is connected with an oxygen conveying pipe.

[0030] Preferably, the oxygen conveying pipe is provided with a third heating device.

[0031] Preferably, the top of the reaction device is connected with the bottom side of the quenching device via a reaction gas conveying pipe.

[0032] Preferably, the quenching device comprises a quenching tower.

[0033] Preferably, the quenching tower contains 3-10 tower plates, such as 3, 4, 5, 8 or 10, preferably 4-6.

[0034] Preferably, the type of the tower plate comprises any one of sieve plate, fixed valve or float valve, preferably sieve plate.

[0035] Preferably, the top of the quenching tower is provided with a trapping water input pipe, which inputs trapping water to cool the reaction gas, absorb hydrogen chloride and wash off catalyst.

[0036] Preferably, a cooling device is arranged between the quenching device and the gas-liquid separation device, which converts dichloroethane and water in the reaction gas into liquid state.

[0037] Preferably, the bottom of the quenching device is provided with a waste water discharge pipe.

[0038] Preferably, the bottom of the gas-liquid separation device is provided with a crude product output pipe, and the top is provided with a gas output pipe.

[0039] Preferably, the gas output pipe is sequentially provided with a gas compression device and a fourth heating device.

[0040] Preferably, the gas output pipeline is connected with the second raw material conveying pipeline.

[0041] The gas discharged from the top of the gas-liquid separation device in the present application is mainly non-condensable gas such as carbon dioxide, carbon monoxide, oxygen, ethylene and nitrogen. After being pressurized and heated by the compressor, the non-condensable gas is sent to the bottom of the reactor as circulating gas to fluidize the catalyst bed. Part of the non-condensable gas can be discharged for incineration to control the pressure stability in the reaction device.

[0042] In a second aspect, the present application also provides a method for preparing dichloroethane by ethylene oxychlorination, which is carried out by using the device system for preparing dichloroethane by ethylene oxychlorination according to the first aspect; the method comprises the following steps:

[0043] (1) The raw materials hydrogen chloride, oxygen and ethylene enter the bottom of the reaction device and are subjected to catalytic reaction under the action of the fluidized catalyst to generate reaction gas containing dichloroethane;

[0044] In the process of the catalytic reaction, the liquid dichloroethane is sprayed into the reaction device through the spraying device between the adjacent heat exchange devices in the reaction device, and the oxygen is introduced into the reaction device through the gas distribution device;

[0045] (2) The reaction gas containing dichloroethane is separated by the multi-stage gas-solid separation device, and the catalyst carried by the reaction gas flows back to the reaction device;

[0046] (3) The reaction gas from which the catalyst is removed enters the quenching device and the gas-liquid separation device in sequence to obtain crude dichloroethane; the non-condensable gas separated by the gas-liquid separation device is introduced into the reaction device as circulating gas.

[0047] The method for preparing dichloroethane by ethylene oxychlorination according to the present application can control the reaction temperature of different bed layers by spraying the liquid dichloroethane into the reaction device through the spraying device between the adjacent heat exchange devices in the reaction device together with the multi-stage heat exchange device, and can adjust the oxygen content in different bed layers by grading the oxygen, and can improve the particle size distribution of the catalyst in the bed layer by recovering the catalyst, so that the ethylene ablation rate is reduced to 0.5%, the hydrogen chloride conversion rate is increased to 99.9%, and the purity of the crude dichloroethane is increased to 99.5%.

[0048] The reaction device of the present application is provided with multi-stage heat exchange devices, and the gas distribution device is arranged between the adjacent heat exchange devices to introduce oxygen. 85-95% of the total oxygen is added from the bottom of the reactor, and the remaining oxygen is distributed to the bed layers between the other heat exchange pipes. By adjusting the distribution ratio of the oxygen, the ethylene ablation rate at the bottom of the reactor can be reduced, and the hydrogen chloride conversion rate at the top of the reactor can be improved.

[0049] Preferably, the raw material hydrogen chloride and oxygen in step (1) are heated by the first heating device and then enter the bottom of the reaction device through the first raw material conveying pipe.

[0050] Preferably, the raw material ethylene is heated by the second heating device and then enters the bottom of the reaction device through the second raw material conveying pipe.

[0051] Preferably, the total mass ratio of oxygen to hydrogen chloride is (0.23-0.30):1, for example, it can be 0.23:1, 0.24:1, 0.25:1, 0.26:1, 0.27:1, 0.28:1 or 0.30:1, etc., but not limited to the listed values, other values not listed in the range are also applicable.

[0052] The total oxygen in the present application includes the oxygen conveyed into the bottom of the reaction device and the oxygen conveyed between the adjacent heat exchange devices through the gas distribution device.

[0053] The mass ratio of ethylene to hydrogen chloride is (0.39-0.48):1, for example, it can be 0.39:1, 0.40:1, 0.41:1, 0.42:1, 0.45:1, 0.47:1 or 0.48:1, etc., but not limited to the listed values, other values not listed in the range are also applicable.

[0054] Preferably, the catalyst includes a metal-supported catalyst.

[0055] Preferably, the metal-supported catalyst uses γ-Al2O3 as the carrier and CuCl2 as the active component; the active component accounts for 6.3-10.6wt% of the metal-supported catalyst, for example, it can be 6.3wt%, 6.5wt%, 7wt%, 7.5wt%, 8wt%, 9wt% or 10.6wt%, etc., but not limited to the listed values, other values not listed in the range are also applicable, preferably 8.5wt%.

[0056] Preferably, the particle size of the catalyst is 20-200um, for example, it can be 20um, 30um, 50um, 80um, 100um, 150um or 200um, etc., but not limited to the listed values, other values not listed in the range are also applicable.

[0057] The median particle size is 50-60um, for example, it can be 50um, 52um, 54um, 56um, 58um, 59um or 60um, etc., but not limited to the listed values, other values not listed in the range are also applicable.

[0058] Preferably, the bed density of the catalyst is 350-500kg / m 3for example, can be 350 kg / m 3 , 380 kg / m 3 , 400 kg / m 3 , 410 kg / m 3 , 450 kg / m 3 , 480 kg / m 3 , 490 kg / m 3 or 500 kg / m 3 , etc., but not only the listed values, other values not listed within the range are also applicable, preferably 400-500 kg / m 3 .

[0059] Preferably, the height of the catalyst bed is 50%-70% of the height of the reaction device, for example, can be 50%, 53%, 55%, 60%, 65%, 68% or 70%, etc., but not only the listed values, other values not listed within the range are also applicable, preferably 55%-65%.

[0060] Preferably, the fluidization gas velocity in the reaction device of step (1) is 0.2-0.8 m / s, for example, can be 0.2 m / s, 0.3 m / s, 0.4 m / s, 0.5 m / s, 0.6 m / s, 0.7 m / s or 0.8 m / s, etc., but not only the listed values, other values not listed within the range are also applicable, preferably 0.4-0.6 m / s.

[0061] Preferably, the temperature of the catalytic reaction is 190-270°C, for example, can be 190°C, 195°C, 198°C, 200°C, 230°C, 250°C or 270°C, etc., but not only the listed values, other values not listed within the range are also applicable.

[0062] Preferably, the pressure of the catalytic reaction is 300-500 kPag, for example, can be 300 kPag, 350 kPag, 400 kPag, 420 kPag, 450 kPag, 470 kPag or 500 kPag, etc., but not only the listed values, other values not listed within the range are also applicable, preferably 350-400 kPag.

[0063] Preferably, the temperature difference of the reaction area of the adjacent heat exchange devices is ≥5°C, for example, can be 5°C, 10°C, 15°C, 20°C, 25°C, 30°C or 40°C, etc., but not only the listed values, other values not listed within the range are also applicable, preferably 10-30°C.

[0064] Preferably, the temperature at the bottom of the reaction device is 240-270℃, for example, it can be 240℃, 245℃, 250℃, 255℃, 260℃, 265℃ or 270℃, etc., but not limited to the listed values, other values not listed in the range are also applicable, preferably 250-260℃.

[0065] Preferably, the temperature at the top of the reaction device is 190-250℃, for example, it can be 190℃, 195℃, 200℃, 210℃, 230℃, 240℃ or 250℃, etc., but not limited to the listed values, other values not listed in the range are also applicable, preferably 200-230℃.

[0066] The present application realizes high ethylene conversion at the bottom of the reaction device and low ablation rate of ethylene at the top of the reaction device by spraying liquid dichloroethane into the reaction device through the spraying device between adjacent heat exchange devices in the reaction device during the catalytic reaction, and controlling the temperature of different bed layers in the reaction device by the reaction device and the multi-stage heat exchange device, so that the temperature difference of the reaction area of adjacent heat exchange devices is ≥5℃, the temperature at the bottom of the reaction device is 240-270℃, and the temperature at the top of the reaction device is 190-250℃.

[0067] Preferably, the catalyst separated by the multi-stage gas-solid separation device in step (2) is refluxed to the lower part of different vertical heat exchange members according to particle size from large to small.

[0068] Specifically, taking 3-stage cyclone separators and 3-stage heat exchange members as an example: the 1-stage cyclone separator mainly removes catalysts with a particle size ≥50um, and the catalyst is refluxed to the lower part of the 1-stage heat exchange member area; the 2-stage cyclone separator mainly removes catalysts with a particle size ≥30um, and the catalyst is refluxed to the lower part of the 2-stage heat exchange member area; and the 3-stage cyclone separator mainly removes catalysts with a particle size ≥5um, and the catalyst is refluxed to the lower part of the 3-stage heat exchange member area. The balanced distribution of catalysts in the fluidized bed layer is realized, large particle sizes are concentrated in the lower part of the bed layer, and small particle sizes are concentrated in the upper part of the bed layer, thereby reducing the side reactions in the high-temperature area at the lower part of the bed layer, greatly reducing the generation of carbon tetrachloride, trichloroethane and other by-products, and improving the hydrogen chloride conversion rate in the low-temperature area at the upper part of the bed layer.

[0069] Preferably, the gage pressure of the quenching device in step (3) is 300-500kPag, for example, it can be 300kPag, 350kPag, 400kPag, 420kPag, 450kPag, 470kPag or 500kPag, etc., but not limited to the listed values, other values not listed in the range are also applicable, preferably 350-400kPag.

[0070] Preferably, the tower bottom temperature of the quenching device is 100-120°C, for example, it can be 100°C, 105°C, 108°C, 110°C, 113°C, 115°C or 120°C, etc., but not limited to the listed values, other values not listed in the range are also applicable, preferably 105-110°C.

[0071] Preferably, the reaction gas is cooled to 30-60°C by the cooling device before entering the gas-liquid separation device, for example, it can be 30°C, 35°C, 40°C, 45°C, 50°C, 55°C or 60°C, etc., but not limited to the listed values, other values not listed in the range are also applicable, preferably 35-40°C.

[0072] Preferably, the non-condensable gas separated by the gas-liquid separation device is pressurized by the gas compression device and heated by the heating device, and then enters the bottom of the reaction device as circulating gas.

[0073] As a preferred technical solution of the present application, the method comprises the following steps:

[0074] (1) The raw material hydrogen chloride and oxygen are heated by the first heating device and then enter the bottom of the reaction device through the first raw material conveying pipeline; the raw material ethylene is heated by the second heating device and then enters the bottom of the reaction device through the second raw material conveying pipeline, and catalytic reaction is carried out under the action of the fluidized catalyst to generate reaction gas containing dichloroethane;

[0075] During the catalytic reaction, liquid dichloroethane is sprayed into the reaction device through the spraying device between adjacent heat exchange devices in the reaction device, and oxygen is introduced into the reaction device through the gas distribution device;

[0076] The total mass ratio of oxygen to hydrogen chloride is (0.23-0.30):1, and the mass ratio of ethylene to hydrogen chloride is (0.39-0.48):1; the catalyst comprises a metal-supported catalyst, γ-Al2O3 is used as the carrier, and CuCl2 is used as the active component, the active component accounts for 6.3-10.6wt% of the metal-supported catalyst; the particle size of the catalyst is 20-200um, and the median particle size is 50-60um; the bed density of the catalyst is 350-500kg / m 3 ; the bed height of the catalyst is 50%-70% of the height of the reaction device;

[0077] The fluidization gas velocity in the reaction device is 0.2-0.8m / s; the temperature of the catalytic reaction is 190-270°C; the table pressure of the catalytic reaction is 300-500kPag; the temperature difference of the reaction area of the adjacent heat exchange devices is ≥5°C; the bottom temperature of the reaction device is 240-270°C; and the top temperature of the reaction device is 190-250°C;

[0078] (2) The dichloroethane-containing reaction gas is separated by a multi-stage gas-solid separation device, and the catalyst carried in the reaction gas is returned to the lower part of different vertical heat exchange members according to particle size from large to small;

[0079] (3) After the reaction gas from which the catalyst is removed enters the quenching device, it is cooled to 30-60 DEG C by the cooling device, enters the gas-liquid separation device, and the non-condensable gas separated by the gas-liquid separation device is pressurized by the gas compression device and heated by the heating device, and then enters the bottom of the reaction device as the circulating gas;

[0080] The surface pressure of the quenching device is 300-500 kPag, and the bottom temperature of the quenching device is 100-120 DEG C.

[0081] Compared with the prior art, the present application has at least the following beneficial effects:

[0082] (1) The reaction device of the device system for preparing dichloroethane by ethylene oxychlorination provided by the present application is provided with multi-stage heat exchange devices, and a spraying device is arranged between adjacent heat exchange devices, so that the reaction device is accurately controlled in sections, hydrogen chloride can inhibit the ablation of ethylene, the temperature at the bottom of the reaction device is increased to improve the reaction rate of ethylene, and the temperature at the top of the reaction device is reduced to reduce the ablation of ethylene.

[0083] (2) The method for preparing dichloroethane by ethylene oxychlorination provided by the present application can reduce the ablation rate of ethylene from 4.5% to 0.5%, increase the conversion rate of hydrogen chloride from 99.4% to 99.9%, and increase the purity of crude dichloroethane from 98.6% to 99.5%, thereby greatly improving the economic benefits of the oxychlorination process. BRIEF DESCRIPTION OF DRAWINGS

[0084] Figure 1 is a schematic diagram of the device system for preparing dichloroethane by ethylene oxychlorination in Example 1.

[0085] Figure 2 is a schematic diagram of the device system for preparing dichloroethane by ethylene oxychlorination in Comparative Example 1.

[0086] In the figure: 1-reaction device; 2-quenching tower; 3-gas-liquid separator; 4-first vertical heat exchange member; 5-second vertical heat exchange member; 6-third vertical heat exchange member; 7-sprayer; 8-gas distributor; 9-cyclone separator; 10-first raw material conveying pipeline; 11-second raw material conveying pipeline; 12-first heater; 13-second heater; 14-oxygen conveying pipeline; 15-third heater; 16-captured water input pipeline; 17-cooler; 18-rough product output pipeline; 19-gas output pipeline; 20-gas compressor; 21-fourth heater; 22-vertical heat exchange member. DETAILED DESCRIPTION

[0087] The technical solutions of the present application will be further described below in conjunction with the drawings and through specific embodiments.

[0088] The present application will be further described below. However, the examples described below are only simple examples of the present application and do not represent or limit the protection scope of the present application, and the protection scope of the present application is subject to the claims.

[0089] It should be understood that, in the description of the present application, the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0090] It should be noted that, in the description of the present application, unless otherwise explicitly specified and limited, the terms "provided", "connected", "connected" should be understood broadly, for example, it can be a fixed connection, or it can be a detachable connection, or an integral connection; it can be a mechanical connection, or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be a communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0091] It should be understood by those skilled in the art that the present application necessarily includes necessary pipelines, conventional valves and general pump equipment for realizing the complete process, but the above content does not belong to the main inventive points of the present application, and those skilled in the art can add layout by themselves based on the process flow and equipment structure selection, and the present application does not make special requirements and specific limitations on this.

[0092] Example 1

[0093] The present embodiment provides a device system for preparing dichloroethane by ethylene oxychlorination, and a schematic diagram thereof is shown in Figure 1 .

[0094] The device system comprises a reactor 1, a quenching tower 2 and a gas-liquid separator 3 connected in a loop; the reactor 1 is a fluidized bed reactor with a diameter of 4.3 m.

[0095] The reactor 1 is provided with a catalyst; the reactor 1 is sequentially provided with three vertical heat exchange members from bottom to top, which are a first vertical heat exchange member 4, a second vertical heat exchange member 5 and a third vertical heat exchange member 6; staggered layout is adopted, the length of each column pipe is 5 m, the first vertical heat exchange member 4 is provided with 24 groups of U-shaped column pipes, each group contains 12 column pipes, the column pipe diameter is 100 mm, the second vertical heat exchange member 5 is provided with 24 groups of U-shaped column pipes, each group contains 18 column pipes, the column pipe diameter is 80 mm, and the third vertical heat exchange member 6 is provided with 24 groups of U-shaped column pipes, each group contains 24 column pipes, and the column pipe diameter is 65 mm. The vertical heat exchange members are connected with a boiler water conveying pipeline.

[0096] Sprayers 7 and gas distributors 8 are arranged between adjacent vertical heat exchange members.

[0097] The inside top of the reactor 1 is provided with three cyclone separators 9 from left to right, which are a first cyclone separator, a second cyclone separator and a third cyclone separator.

[0098] A first raw material conveying pipeline 10 and a second raw material conveying pipeline 11 are arranged at one side of the bottom of the reactor 1.

[0099] A first heater 12 is arranged on the first raw material conveying pipeline 10.

[0100] A second heater 13 is arranged on the second raw material conveying pipeline 11.

[0101] The gas distributor 8 is connected with an oxygen conveying pipeline 14.

[0102] A third heater 15 is arranged on the oxygen conveying pipeline 14.

[0103] The top of the reactor 1 is connected with one side of the bottom of a quench tower 2 through a reaction gas conveying pipeline;

[0104] The quench tower 2 contains 8 tower plates; the type of the tower plate is a sieve plate.

[0105] A catch water input pipeline 16 is arranged at the top of the quench tower 2.

[0106] A cooler 17 is arranged between the quench tower 2 and a gas-liquid separator 3.

[0107] A crude product output pipeline 18 is arranged at the bottom of the gas-liquid separator 3, and a gas output pipeline 19 is arranged at the top of the gas-liquid separator 3.

[0108] A gas compressor 20 and a fourth heater 21 are sequentially arranged on the gas output pipeline 19.

[0109] The gas output pipeline 19 is connected with the second raw material conveying pipeline 11.

[0110] Comparative Example 1

[0111] The present comparative example provides a device system for preparing dichloroethane by ethylene oxychlorination, a schematic diagram of which is shown in Figure 2 .

[0112] The device system comprises a reactor 1, a quenching tower 2 and a gas-liquid separator 3 connected in a loop; the reactor 1 has a diameter of 4.3 m and is a fluidized bed reactor.

[0113] The reactor 1 is provided with a catalyst; the reactor 1 is provided with a vertical heat exchange member, and the length of the column tube is 15 m, 24 groups of U-shaped column tubes are arranged, each group contains 12 column tubes, and the diameter of the column tube is 100 mm.

[0114] The inside top of the reactor 1 is provided with a two-stage cyclone separator 9.

[0115] One side of the bottom of the reactor 1 is provided with a first raw material conveying pipe 10 and a second raw material conveying pipe 11;

[0116] The first raw material conveying pipe 10 is provided with a first heater 12;

[0117] The second raw material conveying pipe 11 is provided with a second heater 13; and the oxygen conveying pipe 14 is provided with a third heater 15.

[0118] The top of the reactor 1 is connected to one side of the bottom of the quenching tower 2 through a reaction gas conveying pipe;

[0119] The quenching tower 2 contains 8 tower plates; the type of the tower plate is sieve plate;

[0120] The top of the quenching tower 2 is provided with a catch water input pipe 16;

[0121] A cooler 17 is arranged between the quenching tower 2 and the gas-liquid separator 3;

[0122] The bottom of the gas-liquid separator 3 is provided with a crude product output pipe 18, and the top is provided with a gas output pipe 19;

[0123] The gas output pipe 19 is sequentially provided with a gas compressor 20 and a fourth heater 21;

[0124] The gas output pipe 19 is connected to the second raw material conveying pipe 11.

[0125] Application Example 1

[0126] The present application example provides a method for preparing dichloroethane by ethylene oxychlorination, which is carried out by using the device system for preparing dichloroethane by ethylene oxychlorination provided in the embodiment 1; the method comprises the following steps:

[0127] (1) the raw material hydrogen chloride and oxygen are heated by a first heater and then enter the bottom of the reactor through a first raw material conveying pipe; the raw material ethylene is heated by a second heater and then enters the bottom of the reactor through a second raw material conveying pipe, and catalytic reaction is carried out under the action of the fluidized catalyst to generate reaction gas containing dichloroethane;

[0128] During the catalytic reaction, liquid dichloroethane is sprayed into the reactor through a sprayer between adjacent vertical heat exchange members in the reactor, and oxygen is introduced into the reactor through a gas distributor;

[0129] The total mass ratio of oxygen to hydrogen chloride is 0.23:1, and the mass ratio of ethylene to hydrogen chloride is 0.4:1; the mass ratio of the oxygen introduction amount between the primary vertical heat exchange member and the secondary vertical heat exchange member to the hydrogen chloride feed is 0.02:1, and the mass ratio of the oxygen introduction amount between the secondary vertical heat exchange member and the tertiary vertical heat exchange member to the hydrogen chloride feed is 0.05:1;

[0130] Under full load, the hydrogen chloride feed amount is 29.5 t / h, and the circulating gas flow is 15000 Nm 3 / h;

[0131] The catalyst comprises a metal-supported catalyst, γ-Al2O3 is used as the carrier, and CuCl2 is used as the active component, the active component accounts for 8.5wt% of the metal-supported catalyst; the average particle size of the catalyst is 50-60um. The reactor is filled with 80t of the catalyst, the bed density of the catalyst is 400kg / m 3 ; the bed height of the catalyst is 60% of the height of the reactor;

[0132] The fluidization gas velocity in the reactor is 0.4m / s; the gauge pressure of the catalytic reaction is 350kPag; the temperature in the primary vertical heat exchange member area is controlled at 260℃, the temperature in the secondary vertical heat exchange member area is controlled at 230℃, and the temperature in the tertiary vertical heat exchange member area is controlled at 200℃,

[0133] (2) the reaction gas containing dichloroethane is separated by a tertiary cyclone separator, and the catalyst carried in the reaction gas is returned to the lower part of different vertical heat exchange members according to particle size from large to small; the catalyst with a particle size of ≥50um separated by a first cyclone separator is discharged to the lower part of the primary vertical heat exchange member, the catalyst with a particle size of ≥30um separated by a second cyclone separator is discharged to the lower part of the secondary vertical heat exchange member, and the catalyst with a particle size of ≥5um separated by a third cyclone separator is discharged to the lower part of the tertiary vertical heat exchange member;

[0134] (3) The reaction gas without catalyst enters the quench tower, 12 t / h of capture water is added at the top of the quench tower, the reaction gas is cooled to 108℃, and then is cooled to 35℃ by a cooler, and then enters a gas-liquid separator to obtain crude dichloroethane; the non-condensable gas separated from the gas-liquid separator is pressurized by a gas compressor and heated by a heater, and then enters the bottom of the reactor as a circulating gas;

[0135] The gauge pressure of the quench tower is 340 kPag; and the bottom temperature of the quench tower is 108℃.

[0136] The application example adopts a multi-stage heat exchange + multi-stage cyclone discharge position + oxygen distribution scheme, and the effect is the best, the actual operation of ethylene ablation rate is 0.5%, the hydrogen chloride conversion rate is 99.9%, and the crude dichloroethane purity is 99.5%.

[0137] Application Comparative Example 1

[0138] The application comparative example provides a method for preparing dichloroethane by ethylene oxychlorination, which is carried out by using the device system for preparing dichloroethane by ethylene oxychlorination provided in the embodiment 1; the method comprises the following steps:

[0139] (1) The raw material hydrogen chloride and oxygen are heated by a first heater, and then enter the bottom of the reactor through a first raw material conveying pipeline; the raw material ethylene is heated by a second heater, and then enters the bottom of the reactor through a second raw material conveying pipeline, and is subjected to catalytic reaction under the action of the fluidized catalyst to generate reaction gas containing dichloroethane;

[0140] During the catalytic reaction, liquid dichloroethane is sprayed into the reactor through a sprayer between adjacent vertical heat exchange members in the reactor;

[0141] The total mass ratio of oxygen to hydrogen chloride is 0.25:1, and the mass ratio of ethylene to hydrogen chloride is 0.4:1; the hydrogen chloride feeding amount is 29.5 t / h, and the circulating gas flow is 15000 Nm 3 / h under full load;

[0142] The catalyst comprises a metal supported catalyst, γ-Al2O3 is used as a carrier, and CuCl2 is used as an active component, the active component accounts for 8.5wt% of the metal supported catalyst; the average particle size of the catalyst is 50-60 um; the reactor is filled with 80 t of the catalyst, the bed density of the catalyst is 400 kg / m 3 ; and the bed height of the catalyst is 60% of the height of the reactor.

[0143] The fluidization gas velocity in the reactor is 0.4 m / s; the gauge pressure of the catalytic reaction is 350 kPag; the temperature of the first vertical heat exchange member region is controlled at 250℃, the temperature of the second vertical heat exchange member region is controlled at 230℃, and the temperature of the third vertical heat exchange member region is controlled at 200℃,

[0144] (2) The reaction gas containing dichloroethane is separated by the third cyclone separator, and the separated catalyst is discharged to the lower part of the first vertical heat exchange member;

[0145] (3) The reaction gas from which the catalyst is removed enters the quenching tower, 12 t / h of capture water is added to the top of the quenching tower, the reaction gas is cooled to 108℃, and then is cooled to 35℃ by a cooler, and then enters a gas-liquid separator to obtain crude dichloroethane; the incondensable gas separated from the gas-liquid separator is treated by pressurization by a gas compressor and temperature rise by a heater, and then enters the bottom of the reactor as a circulating gas;

[0146] The gauge pressure of the quenching tower is 340 kPag; and the bottom temperature of the quenching tower is 108℃.

[0147] The application example provides an ethylene oxychlorination method for preparing dichloroethane, which is carried out by using the device system for preparing dichloroethane by ethylene oxychlorination provided in the embodiment 1; the method comprises the following steps:

[0148] Application Example 2

[0149] The application example provides an ethylene oxychlorination method for preparing dichloroethane, which is carried out by using the device system for preparing dichloroethane by ethylene oxychlorination provided in the embodiment 1; the method comprises the following steps:

[0150] (1) The raw material hydrogen chloride and oxygen are heated by a first heater, and then enter the bottom of the reactor through a first raw material conveying pipeline; the raw material ethylene is heated by a second heater, and then enters the bottom of the reactor through a second raw material conveying pipeline, and catalytic reaction is carried out under the action of the fluidized catalyst to generate reaction gas containing dichloroethane;

[0151] During the catalytic reaction, liquid dichloroethane is sprayed into the reactor through a sprayer between adjacent vertical heat exchange members in the reactor;

[0152] The total mass ratio of oxygen to hydrogen chloride is 0.25:1, and the mass ratio of ethylene to hydrogen chloride is 0.4:1; under full load, the hydrogen chloride feeding amount is 29.5 t / h, and the circulating gas flow is 15000 Nm 3 / h;

[0153] The catalyst comprises a metal supported catalyst, γ-Al2O3 as a carrier, CuCl2 as an active component, the active component accounts for 8.5wt% of the metal supported catalyst; the average particle size of the catalyst is 50-60um. The reactor is filled with 80t of the catalyst, the bed density of the catalyst is 400kg / m 3 ; the bed height of the catalyst is 60% of the height of the reactor;

[0154] The fluidization gas velocity in the reactor is 0.4m / s; the gauge pressure of the catalytic reaction is 350kPag; the temperature control of the first vertical heat exchange member region is 250℃, the temperature control of the second vertical heat exchange member region is 230℃, the temperature control of the third vertical heat exchange member region is 200℃,

[0155] (2) The reaction gas containing dichloroethane is separated by three-stage cyclone separators, the catalyst with a particle size ≥50um is discharged to the lower part of the first vertical heat exchange member by a first cyclone separator, the catalyst with a particle size ≥30um is discharged to the lower part of the second vertical heat exchange member by a second cyclone separator, and the catalyst with a particle size ≥5um is discharged to the lower part of the third vertical heat exchange member by a third cyclone separator;

[0156] (3) The reaction gas from which the catalyst is removed enters the quenching tower, 12t / h of capture water is added to the top of the quenching tower, the reaction gas is cooled to 108℃, then is cooled to 35℃ by a cooler, and then enters a gas-liquid separator to obtain crude dichloroethane; the incondensable gas separated by the gas-liquid separator is treated by pressurization by a gas compressor and temperature rise by a heater, and then enters the bottom of the reactor as a circulating gas;

[0157] The gauge pressure of the quenching tower is 340kPag; the bottom temperature of the quenching tower is 108℃.

[0158] The application example of the present application adopts a multi-stage heat exchange + multi-stage cyclone discharge position scheme, and in actual operation, the ethylene ablation rate is 1%, the hydrogen chloride conversion rate is 99.8%, and the purity of crude dichloroethane is 99.3% due to the fact that oxygen is not introduced through a gas distributor between adjacent vertical heat exchange members.

[0159] Application Example 3

[0160] The application example of the present application provides a method for preparing dichloroethane by ethylene oxychlorination, which is carried out by using the device system for preparing dichloroethane by ethylene oxychlorination provided in the application example 1; the method comprises the following steps:

[0161] (1) The raw material hydrogen chloride and oxygen are heated by a first heater, and then enter the bottom of the reactor through a first raw material conveying pipeline; the raw material ethylene is heated by a second heater, and then enters the bottom of the reactor through a second raw material conveying pipeline, and is subjected to a catalytic reaction under the action of the fluidized catalyst to generate reaction gas containing dichloroethane;

[0162] The total mass ratio of oxygen and hydrogen chloride is 0.25:1, the mass ratio of ethylene and hydrogen chloride is 0.4:1; the hydrogen chloride feeding amount under full load is 29.5t / h, and the circulating gas flow is 15000Nm 3 / h;

[0163] The catalyst comprises a metal supported catalyst, γ-Al2O3 is used as the carrier, CuCl2 is used as the active component, and the active component accounts for 8.5wt% of the metal supported catalyst; the average particle size of the catalyst is 50-60um; 80t of the catalyst is filled in the reactor, and the bed density of the catalyst is 400kg / m 3 ; the bed height of the catalyst is 60% of the height of the reactor;

[0164] The fluidization gas speed in the reactor is 0.4m / s; the reactor bed temperature is 240℃, and the reactor pressure is 450kPag;

[0165] (2) the reaction gas containing dichloroethane is separated by two-stage cyclone separators;

[0166] (3) the reaction gas from which the catalyst is removed enters the quenching tower, 12t / h of capture water is added to the top of the quenching tower, the reaction gas is cooled to 108℃, and then is cooled to 35℃ by a cooler, and then enters a gas-liquid separator to obtain crude dichloroethane; the incondensable gas separated from the gas-liquid separator is treated by pressurization by a gas compressor and temperature rising by a heater, and then enters the bottom of the reactor as the circulating gas;

[0167] The gauge pressure of the quenching tower is 340kPag; and the bottom temperature of the quenching tower is 108℃.

[0168] The device system used in the application comparative example is different from that in application example 1, the reactor only has one-stage vertical heat exchange component, the top of the reactor is only provided with two-stage cyclone separators, and there is no sprayer and gas distributor; in actual operation, the ethylene ablation rate is 4.5%, the hydrogen chloride conversion rate is 99.4%, and the crude dichloroethane purity is 98.6%.

[0169] The applicant declares that the application is illustrated by the above examples to explain the detailed structural features of the application, but the application is not limited to the above detailed structural features, that is, it does not mean that the application must rely on the above detailed structural features to be implemented. It should be understood by those skilled in the art that any improvement of the application, equivalent replacement of the components selected by the application, increase of auxiliary components, selection of specific modes, etc. fall within the protection scope and disclosure scope of the application.

[0170] The preferred embodiments of the present application are described in detail above, but the present application is not limited to the specific details of the above-described embodiments, and various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application.

Claims

1. A process for the oxychlorination of ethylene to dichloroethane, characterized in that, The method is carried out using an ethylene oxychlorination system to produce ethylene dichloride; The device system includes a reaction device, a quenching device and a gas-liquid separation device which are cyclically connected; The reaction device is provided with a catalyst; the reaction device is provided with multiple stages of heat exchange devices from bottom to top; a spray device and a gas distribution device are provided between adjacent heat exchange devices; and a multi-stage gas-solid separation device is provided on the top of the inner side of the reaction device; The method comprises the following steps: (1) The raw materials hydrogen chloride, oxygen, and ethylene enter the bottom of the reaction device and undergo a catalytic reaction under the action of a catalyst in a fluidized state to generate a reaction gas containing ethylene dichloride; During the catalytic reaction, liquid dichloroethane is sprayed into the reaction device through a spray device between adjacent heat exchange devices in the reaction device, and oxygen is introduced into the reaction device through a gas distribution device; (2) the reaction gas containing ethylene dichloride is separated by a multi-stage gas-solid separation device, and the catalyst carried in the reaction gas is refluxed into the reaction device; (3) The reaction gas after the catalyst is removed enters the quenching device and the gas-liquid separation device in sequence to obtain crude dichloroethane; the non-condensable gas separated by the gas-liquid separation device enters the reaction device as circulating gas.

2. The method of claim 1, wherein, The heat exchange device includes a vertical heat exchange component.

3. The method of claim 2, wherein, The number of stages of the vertical heat exchange components is 2-5.

4. The method of claim 3, wherein, The number of stages of the vertical heat exchange components is 3.

5. The method of claim 3, wherein, Each level of vertical heat exchange components includes 20-30 groups of U-shaped tubes, each group of U-shaped tubes contains 2n tubes, and n is 5-12.

6. The method of claim 5, wherein, The diameter of the tubes is independently 50-100 mm.

7. The method of claim 6, wherein, The diameters of the tubes are independently 65 mm, 80 mm or 100 mm.

8. The method of claim 5, wherein, The length of the tubes is independently 3-15 m.

9. The method of claim 8, wherein, The length of each tube is independently 4-5 m.

10. The method of claim 3, wherein, The number, diameter and length of the U-shaped tubes in the vertical heat exchange components of the same level are consistent.

11. The method of claim 3, wherein, The positions of the U-shaped tubes in adjacent vertical heat exchange components are staggered.

12. The method of claim 3, wherein, The vertical heat exchange component is connected to the boiler water delivery pipeline.

13. The method of claim 1, wherein, The number of stages of the gas-solid separation device is the same as the number of stages of the vertical heat exchange components.

14. The method of claim 1, wherein, The gas-solid separation device includes a cyclone separator.

15. The method of claim 1, wherein, The type of the reaction device is a fluidized bed reaction device.

16. The method of claim 1, wherein, A first raw material delivery pipeline and a second raw material delivery pipeline are provided on one side of the bottom of the reaction device.

17. The method of claim 16, wherein, The first raw material conveying pipeline is provided with a first heating device.

18. The method of claim 16, wherein, The second raw material conveying pipeline is provided with a second heating device.

19. The method of claim 1, wherein, The gas distribution device is connected to the oxygen delivery pipeline.

20. The method of claim 19, wherein, The oxygen delivery pipeline is provided with a third heating device.

21. The method of claim 1, wherein, The top of the reaction device is connected to one side of the bottom of the quenching device via a reaction gas delivery pipeline.

22. The method of claim 1, wherein, The quenching device includes a quenching tower.

23. The method of claim 22, wherein, The quenching tower contains 3-10 tower plates.

24. The method of claim 23, wherein, The quenching tower contains 4-6 tower plates.

25. The method of claim 23, wherein, The type of the tower plate includes any one of a sieve plate, a fixed valve plate or a floating valve plate.

26. The method of claim 25, wherein, The type of the tray is a sieve tray.

27. The method of claim 22, wherein, A captured water input pipeline is provided on the top of the quenching tower.

28. The method of claim 1, wherein, A cooling device is provided between the quenching device and the gas-liquid separation device.

29. The method of claim 1, wherein, The bottom of the gas-liquid separation device is provided with a crude product output pipeline, and the top is provided with a gas output pipeline.

30. The method of claim 29, wherein, The gas output pipeline is sequentially provided with a gas compression device and a fourth heating device.

31. The method of claim 29, wherein, The gas output pipe is connected with a second raw material conveying pipe.

32. The method of claim 1, wherein, The raw material hydrogen chloride and oxygen in step (1) are heated by a first heating device and then enter the bottom of the reaction device through a first raw material conveying pipe.

33. The method of claim 1, wherein, The raw material ethylene is heated by a second heating device and then enters the bottom of the reaction device through a second raw material conveying pipe.

34. The method of claim 1, wherein, The total mass ratio of oxygen to hydrogen chloride is (0.23-0.30):1, and the mass ratio of ethylene to hydrogen chloride is (0.39-0.48):

1.

35. The method of claim 1, wherein, The catalyst comprises a metal supported catalyst.

36. The method of claim 35, wherein, The metal supported catalyst uses γ-Al2O3 as a carrier and CuCl2 as an active component, and the active component accounts for 6.3-10.6wt% of the metal supported catalyst.

37. The method of claim 36, wherein, The active component accounts for 8.5wt% of the metal supported catalyst.

38. The method of claim 1, wherein, The particle size of the catalyst is 20-200um, and the median particle size is 50-60um.

39. The method of claim 1, wherein, The bed density of the catalyst is 350-500 kg / m 3 .

40. The method of claim 39, wherein, The bed density of the catalyst is 400-500 kg / m 3 .

41. The method of claim 1, wherein, The bed height of the catalyst is 50%-70% of the height of the reaction device.

42. The method of claim 41, wherein, The bed height of the catalyst is 55%-65% of the height of the reaction device.

43. The method of claim 1, wherein, The fluidization gas velocity in the reaction device in step (1) is 0.2-0.8m / s.

44. The method of claim 43, wherein, The fluidization gas velocity in the reaction device in step (1) is 0.4-0.6m / s.

45. The method of claim 1, wherein, The temperature of the catalytic reaction is 190-270℃.

46. The method of claim 1, wherein, The gauge pressure of the catalytic reaction is 300-500kPag.

47. The method of claim 46, wherein, The gauge pressure of the catalytic reaction is 350-400kPag.

48. The method of claim 1, wherein, The temperature difference of the reaction areas of the adjacent heat exchange devices is ≥5℃.

49. The method of claim 48, wherein, The temperature difference of the reaction areas of the adjacent heat exchange devices is 10-30℃.

50. The method of claim 1, wherein, The bottom temperature of the reaction device is 240-270℃.

51. The method of claim 50, wherein, The bottom temperature of the reaction device is 250-260℃.

52. The method of claim 1, wherein, The top temperature of the reaction device is 190-250℃.

53. The method of claim 52, wherein, The top temperature of the reaction device is 200-230℃.

54. The method of claim 1, wherein, The catalyst separated by the multi-stage gas-solid separation device in step (2) is returned to the lower part of different vertical heat exchange members according to the particle size from large to small.

55. The method of claim 1, wherein, The gauge pressure of the quenching device in step (3) is 300-500kPag.

56. The method of claim 55, wherein, The gauge pressure of the quenching device in step (3) is 350-400kPag.

57. The method of claim 1, wherein, The bottom temperature of the quenching device is 100-120℃.

58. The method of claim 57, wherein, The bottom temperature of the quenching device is 105-110℃.

59. The method of claim 1, wherein, The reaction gas is cooled to 30-60℃ by a cooling device before entering the gas-liquid separation device.

60. The method of claim 59, wherein, The reaction gas is cooled to 35-40℃ by a cooling device before entering the gas-liquid separation device.

61. The method of claim 1, wherein, The non-condensable gas separated by the gas-liquid separation device is pressurized by a gas compression device and heated by a heating device, and then enters the bottom of the reaction device as circulating gas.

Images